Adding lighting kits to TTS models

[Spireblade]

Hi, I am sure this issue has been discussed elsewhere but I cant find it so firstly , my apologies.

Having recently moved house and with no layout setup yet I decided to keep my interest up by installing a lighting kit to a few locos. My first attempt with a Class 47TTS model seemed to go very well until it came to testing. All lights worked....great start, huge smile. Sound still worked, motor still worked etc...

My issue is that somehow the directional lighting is the wrong way around, red going forwards etc. Also a small way along my test track the lights flickered and everything cut out, although no need to reset anything, just help the loco on it's way with my hand.

Is there a quick fix to this? I have followed the manufacturers instructions as in which pin to solder to etc....

 

Cheers!

[Spireblade]

I have just done my Class 55 St Paddy which is much simpler and have exactly the same issue.

 

Will swapping over white an yellow wires on the socket cure it?

[Chrissaf]

Draw out how you have wired them up and post an image of it. State LED colours and wire colours in the drawing. See image below for an example.

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This image below copied from a previous post I made, showing the correct wiring for directional lighting. The resistor values shown are just typical and can vary.

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/media/tinymce_upload/47e7e0ac7f54b3fdaed40f5670d040ce.jpg

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Will swapping over white an yellow wires on the socket cure it?

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As a last resort, but do compare your wiring to above first. I wouldn't swop the wires on the socket unless they are definitely on the wrong pins (see below), else the socket wiring will be non standard (unless of course they are wires you have provided on the socket and not white or yellow in colour). If the wires are 'white & yellow' then I would swop the white / yellow wires at the LED ends to maintain the correct socket NEM652 wiring colour scheme. But at the end of the day it is your loco and your choice, but it may confuse others that might own the loco after you if you diverge away from the standard.

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/media/tinymce_upload/2e578ccf30d79761a1e63e23a3751f32.jpg

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Image courtesy of Brian Lambert's web site.

 

[Spireblade]

Well, issue sorted on the 55. Swapped yellow and white over and works as it should. I'll re do the 47 and see what happens.

[Spireblade]

Did the same with the 47, lights now fine.

The sound however was ok for about 20 seconds and now sounds like a crumpled crisp packet, decreasing to just a crackle. :-/ 

[Spireblade]

I seem to remember something about putting a resistor on the blue wire?

[96RAF]

I seem to remember something about putting a resistor on the blue wire?

As shown in Chris’s diagram above.

The lighting functions are not protected at the decoder and overloading them will damage the decoder outputs.

Rob

[Spireblade]

Cheers!

[Fishmanoz]

The resistor’s job isn’t to protect the decoder, it’s to protect the LED.  Without the resistor, the decoder has sufficient current capability, 100mA, and voltage to destroy the LED without decoder overload.

 

There‘s also nothing wrong with a resistor in the blue wire, it just adds to the total resistance in series with the LED which will make it dimmer.

[Chrissaf]

Fishy is correct in principle, but with a caveat.

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If the LED gets destroyed (because there is no resistor) then the LED [9 times out of 10] will go 'short circuit' and not 'open circuit'. Going 'short circuit' will then go on to overload the decoder output, with possible subsequent decoder failure. You should ALWAYS include a current limiting resistor with an LED, the only exception to this rule is when you are using a special LED constant current driver circuit.

[morairamike]

Beware condemning the decoder if speaker crackles, in my case it was the original speaker that failed and gave crackle. Hornby changed it but I fitted sugarcube instead. Beware these are 8 ohms speakers so if substitute speaker used make sure it is 8 ohms.

[96RAF]

What I was trying to say is you meed a resistor(s) to limit the current not only to protect the led but to keep the function circuit current within the overload limit of the decoder’s function output, else the decoder will be damaged.

I quote my Class 37 with an Express Models lighting kit comprising 2x red, 2 x markers and 1 x headlight taking the function output to around 100mA, resulting in strange lights goings on. An additional resistor in the blue wire lowered the overall current and all was well again.

Rob

[Spireblade]

I am using the very same Express Models kits so I will take your advice and add the resistor to the blue wire.

I still have to do 2 TTS 37's and a TTS 47 to do.  It's a shame Express don't build one into the kits as standard.

 

Cheers

[olly]

I would try a new speaker just make sure its an 8 ohm speaker 

[96RAF]

express models do have smd resisters on their pcb but not enough for tts use running 5 leds

Rob

[Spireblade]

Thanks for the advice. The resistors work fine, lights a little dimmer as was explained but it looks more realistic anyway. The speaker has been replaced and all is well.

[DEREK123]

Hi Spireblade

I have just bought the Express Kit  (DCC/HY47W - HORNBY Class 47 with Headlight Kit ) .. I am not an electronics wiz but a fair DIYer , but I do have a grandson who is extremely keen for me to fit the lighting  !! 😮

My questions to you are :

1 ..are they relatively easy to install ( I can solder ) and what are the risks to the TTS chip , and any pitfalls I should be aware of ? 

2 ..Is F0 the control for both front and rear head/tail lights .... eg Do I need to amend CVs ?

I hope you or somebody can advise.

Thanks

Derek

 

 

[96RAF]

Derek

The kits come with full instructions for decoders with various numbers of functions. TTS decoders can run F0 (2 functions - one for forward and one for reverse lights) and one other function F25 on diesels.

 

The TTS decoder socket will only have the four outer pins wired - track pickups and motor, so you need to run new wires to the four inner pins - see the 8-pin socket colour code posted many times on the forum or its in the dcc conversion section of the main site. These wires are blue for positive common, white for fwd lights, yellow for reverse lights and green for aux function (cab lights?).

 

obviously the white front lights at one end connect to the red rear lights at the other end and vice-versa.

 

just put an extra 1k resistor in the blue wire where you connect these wires to the kit wires.

Rob

[Spireblade]

Hi Derek

Raf nailed it there. All I can add is that you take extreme care when soldering into the terminals on the socket. I caused myself a problem by accidentally breaking off a couple of the very delicate loco wiring. I ended up rewiring the whole loco as the original wires were so thin and NOT colourcoded to the socket.

[96RAF]

Wiring a total loco in thin black wire is a nuisance for users wanting to reattach a wire or do a bit of fault finding.

 

If I am doing any loco wiring mods I tend to fully rewire using a standard (to me anyhow) colour scheme.

 

Rob

[Spireblade]

I'm glad that you share that view Rob. I find it very confusing and un "user friendly". Out of the 6 loco's I've fitted the kits to, 3 have had a total colour coded rewire..

[DEREK123]

Hi Spireblade and Rob ( RAF ) .... thanks

Well !! ............................

I successfully drilled the 47 body and started to fit the Express Models lit .....  all was going so well but I accidentally knocked  off a front red wire and in resoldering I accidentally unsoldered a blue wire !! ( My soldering isn't bad but I only have one eye following a stroke and I made a bit of a pigs ear of it ) . I called Exress for help / advice and they asked me to return the kit as the Rear Headlamp LED looks to be blown ?..... ( I didn't think it worked when I first assembled the kit ) I had superglued the kit in and getting it out was another disaster ! ......  I now need to get a replacement LED for a front / taillight as well as for the suspect Rear Headlamp ...... the Headcode lights are all okay  ... what do I ask for ( LED spec voltage etc )  and from where  ( maplins ? ) .... Express as I understand only supply full kits !! .... and do not have a detailled wiring diagram  ?

Any further help / advice would be most helpful

( Or should I bin it and start again !! being a bit more careful )

Derek

 

BTW my 47 is fitted with a Hardwired TTS Class 47 Decoder so I didn't need to touch the 8 pin socket.

[DEREK123]

According to the Express Models Website  ( it eventually loaded ) they do have an LED section/department so I will ask them again tomorrow. , but the specific to the kit parts do not appear. 

[96RAF]

Derek

Sorry to hear about your soldering and other misfortunes. Some days it all goes to worms for me and I just walk away from it, do something else for a few hours and try again later.

 

LEDs.

Maplins only go down to 3mm so a bit too big. You need 1.8 to 2mm and preferably what are loosely called lighthouse leds, that have a square block body with a prominent ‘post’ sticking out front, which helps when glueing them in and can be carefully filed down later to look better, taking care you don’t ‘cut to the quick’ (down to the inner electrodes).

 

Spec, just get standard voltage (usually around 2v) and current (usually 10-20mA) these values vary slightly according to the colours, no need for special 12v ones, as the resistors control the current and drop the voltage. I think Exp Mods have these leds but if not try the likes of Farnell or RS Components https://uk.rs-online.com/web/c/displays-optoelectronics/leds-led-accessories/visible-leds/?applied-dimensions=4294303229  or Kytes Lights, http://www.kyteslights.com/index.php?cPath=32&osCsid=6d384e204f0d54c507a1c88140f60f6b   and some other on line shops have them. New Railway Modellers Shop http://www.newmodellersshop.co.uk/electronic-lights.htm scroll down this page.

 

A tip when installing either these light kits or by way of component parts, glue them in last of all, after you have wire up and made sure it all works. I have had to hack out secure parts before when something went wrong.

 

As you are hard wired then just solder the leds to the decoder leads as per colour code before leaving enough slack to be able to get the body off and lay it beside the chassis for testing. In general if you can manage to solder it then there is enough slack.

 

Best of luck with it.

Rob

[Spireblade]

Disaster strikes. Fried TTS decoder!!

Rewired the loco and LED kit....

Tested, after 5 seconds there was a puff of smoke from the decoder. Dead.

All wires are to the correct terminals so no idea what has gone wrong

 

Devastated.